Desalination has been a practical solution to the water shortage problems encountered in numerous countries of the world, in particular, in regions where both the rain fall is scarce and/or the population concentration is high. Numerous commercial-scale desalination plants have been designed, built and operated, such as (i) the multi-stage flash (MSF) type, (ii) the multi-effect desalination type, (iii) the membrane-based reverse osmosis (RO) plants. Hybrid plants, combining the RO and MSF processes can recover higher water yields of high water quality, typically the dissolved solids being less than 500 mg/l, satisfying the requirements of the World Health Organization (WHO) standards. Ion exchange is another method whereby ions of dissolved inorganic salts are replaced with the more desirable ions, and such as a process have been used to minimize the fouling and carry-over to the water.
In general, the conventional desalination plants display three fundamental drawbacks, being: (i) the high energy usage to maintain relatively high temperatures, typically exceeding 110° C., (ii) the high energy consumption of the plant and (iii) the high maintenance costs arising from salt deposition or fouling in the outer surfaces of heat exchangers as well as the corrosion of the tubes. Fouling is accelerated by high solution temperatures and the threshold for high salt deposition from the solution is known to occur when temperatures exceed 80° C. or so.